3. Neutron stars

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When a star dies, it collapses inward, literally squishing its electrons and protons so tightly they fuse together to form neutrons. Imagine something as huge as our sun being compressed down to an object just 10 miles in diameter.

The resulting neutron star is the densest known thing in the universe. How dense? One sugar cube of neutron star material would weigh 100 million tons, and likely make your Starbucks very, very hot.

If you think that’s the weirdest thing in the universe: The famous Crab Nebula contains a neutron star. This glorious chunk of galactic eye candy is the remnant of a giant supernova that could have been seen from Earth as early as 1054, if we weren’t all just diseased, superstitious goat herders back then.